The parent and grandparent applications of the present application, identified hereinabove, disclose methods and compositions for the treatment of tumors exhibiting .beta.-glucuronidase activity or for the treatment of certain bacterial infections having .beta.-glucuronidase activity. Since it is known that certain tumors exhibit high .beta.-glucuronidase activity, as well as do certain bacteria, such tumors or infections may be treated by means of a glucuronide compound having an aglycone which is toxic to the tumor cell or bacterial cell. The conjugated glucuronide is non-toxic but once it comes into contact with the .beta.-glucuronidase at the tumor site or bacteria site, the glucuronide will be deconjugated and the toxic aglycone will destroy the tumor or the bacteria directly at the site of the tumor or of the bacterial infection.
The parent and grandparent applications of the present application disclose the further improvement that the selectivity of such glucuronide compounds toward tumors can be greatly increased and the possible deconjugation of the toxic aglycones in normal parts of the body can be greatly minimized by administering to the patient, prior to or simultaneously with administration of the glucuronide, an alkalinizing agent which will maintain the pH of the rest of the body at a pH of about 7.4. It is known that at a pH of 7.4 and above, glucuronidase activity is substantially nil. Thus, the administration of alkalinizing agent, such as bicarbonates or other basic salts, will substantially decrease and eliminate .beta.-glucuronidase activity which naturally occurs in certain healthy tissues, such as the kidneys, spleen and liver. Such an administration of alkalinizing agent will not diminish the acidity of the tumor cells themselves, however, in view of the naturally low pH of the tumor cells, the mechanism of prior hyperacidification, and the lack of substantial blood perfusion through the tumor areas, as well as other possible mechanisms.
Similarly, it has been reported that the optimum pH of bacterial .beta.-glucuronidase is higher than the optimum pH of the .beta.-glucuronidase of normal healthy internal organs. Therefore, upon alkalinization of the body, the .beta.-glucuronidase activity of the organs will be substantially eliminated, while that of the bacteria, although alkalinized, will still be present.
Before treatment of patients in accordance with the processes of said parent and grandparent applications, it should be ascertained that the particular type of tumor involved has high .beta.-glucuronidase activity. The parent and grandparent applications disclose a number of ways in which this may be done. One way is to assay tumor cells obtained in a biopsy for .beta.-glucuronidase activity. If such a test is positive, then the pharmaceutical compositions discussed hereinabove may be administered. This method cannot be widely used as it is not always feasible to take a biopsy and a method which does not require an operation would be preferred. A second method is the administration of a glucuronide whose aglycon has been labelled with a radioactive isotope. If upon a full body scan it is found that the radioisotope is accumulated at any specific areas of the body, then this will indicate not only the location of the tumor but the fact that the tumor has sufficient .beta.-glucuronidase activity to deconjugate the glucuronide. After this has been determined, the appropriate amount of the glucuronide of choice may be administered. If there are not tumors present, or if the tumors are of the type which do not have .beta.-glucuronidase activity, then there will be no accumulation of radioisotope in the body as the alkalinization step of the present invention eliminates all usual .beta.-glucuronidase activity and the isotope will be passed through the body. This also is not a preferred method as it requires the use of radioactive material and full body X-ray scans.
Another method of diagnosing tumors which are treatable by the above disclosed means is to test for the presence of free glucuronic acid in the urine. While the presence of glucuronides in the urine is common, the presence of free glucuronic acid in the urine, and particularly the presence of increasing amounts of glucuronic acid when tested over a period of several days, is a potent indication of the presence of tumors with .beta.-glucuronidase activity. It is hypothesized that the presence of free glucuronic acid in the urine in cancer patients is caused by the action of .beta.-glucuronidase in the cancer cells on the intercellular filaments and connective tissue. Glucuronic acid is a reaction product of such activity because the intercellular filaments and connective tissue are composed of polymers of which glucuronic acid is an element, and which are known to be substrates for the enzyme .beta.-glucuronidase. A method for distinguishing free glucuronic acid from conjugated glucuronides in the urine is disclosed in said parent application.
This method for diagnosing tumors is a good method as it involves only a urine test. However, this test also has problems of accuracy.